Cucumber (Outside Field Production)

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Growing cucumbers outside can include fruit for both fresh slicing or pickling.  In either instance, plant growth and development, as well as fruit set is important.  The following information is based upon planting seeds 1 foot apart in rows spaced 6 feet apart.  In our trials, direct seeding is as effective, if not more effective than transplanting young plants.  Plasticulture can still be beneficial in helping to control weed pressure, as well as improving fruit quality and appearance to some extent.

In order to grow a great crop of cucumbers start with a preplant soil test, then apply granular nutrients designed to bring your field up to 50-60% of total seasonal requirements.  By applying only a portion of the necessary nutrients before the crop gets going you are doing a lot to prevent nutrient leaching and runoff while still providing a good nutritional start to your season.  Knott’s Handbook for Vegetable Growers recommends: 100-120 units of nitrogen, 100-150 units of phosphate, and 150 units of potash for the entire season.  Sufficient magnesium in balance with calcium is critical in growing great cucumbers.  While cucumbers will tolerate a wider pH range than many crops, they do best at 6.4-6.8.  If your pH is above 6.8, use gypsum (CaSO4) as your calcium source preplant.  Epsum Salts (MgSO4) at 125-200 pounds per acre is an excellent source of Mg prior to planting.

It should be noted that this program is presented as a guideline only based upon research and the experiences with a number of growers.  With the wide variances possible from both soil types and environmental conditions present during any particular season, your actual recommendation can vary from what is presented.  It is always advisable to discuss actual management practices with your local ISP specialist.

Fertility: Apply 16 ounces MetaboliK HV-1, 60 units of N, 50-75 units of P and 75-100 units of K as dry, granular fertilizer preplant or prior to bedding up in plasticulture production.

Transplant Solution: Transplant and/or seeding solution should contain: 8 pounds of 10-4-10 + 24 fluid ounces of PhytoGro Xtra + 16 fluid ounces of MetaboliK SB per 100 gallons of total solution.  Begin fertigation within a week of transplanting or once the first true leaves have emerged on direct seeded platns.

The program in the table is designed for cucumber varities with 55-60 days to harvest, and more or less average weather.  Prolonged cool, cloudy periods will add days to the schedule, and extreme heat can shorten the schedule.  Tissue testing at two critical points in the season will greatly improve managing the crop to great harvest.

Tissue test as the vines first start to runner and there at least 5 leaves per ine, and again just as the first fruit are setting.  For pickling types, just a short tissue test at the onset of runnering is recommended due to the very short growth season.  Recommended range for tissue nutrients: N 2.5-5%, P .25%, K 5%, Ca 3%, Mg .6%, S .75%, Zn 50ppm, Mn 100ppm, Cu 20ppm, Boron 20-60ppm, Fe 40-100ppm, Si 2500-3500ppm.  (Testing silicon, Si, is an additional test).

The following table is based upon a planting population of 7,260 plants per acre; spaced one foot apart in beds six feet apart.  If your population varies from this population, then adjust the recommendations accordingly.

ISP Soluble Plant Foods
Week Per Acre Per 1,000’ row Other notes, micronutrients, Ca, Mg
1-2 8 pounds 10-20-20 & 3 pounds 28-16-7 1 pound 10-20-20 & .5 pound 28-16-7 Include SiGuard MetaboliK HV-1 at 1 teaspoon (5ml) each, every 10 days with any other foliar materials.
3 8 pounds 10-20-20 & 3 pounds 28-16-7 1 pound 10-20-20 & .5 pound 28-16-7 Tissue test as plants are beginning to runner.  If phosphate is low, add 5 pounds 10-45-10 per week to the fertigation.
4 8 pounds 10-20-20 & 3 pounds 28-16-7 1 pound 10-20-20 & .5 pound 28-16-7 Last chance to clean up weeds before the vines begin to runner aggressively.
5 8 pounds 10-20-20, 6 pounds 9-14-24 & 8oz. SiMag58 1 pound 10-20-20, 2.5 pounds 9-14-24, & 1.25oz. (35gms) SiMag58
6 8 pounds 10-20-20, 6 pounds 9-14-24, & 8oz SiMag58 1 pound 10-20-20, 2.5 pounds 9-14-24, & 1.25oz (35gms) SiMag58 Tissue test as the plants begin to set fruit.  Switch from SiGuard to SiMag (foliar) at 1 teaspoon (5ml) per gallon every 5-7 days with other foliar materials.  Adjust all nutrient applications per tissue test results.  Continue MetaboliK HV-1 at 1 teaspoon (5ml) per gallon at 7-10 day intervals with other foliar materials.
7 8 pounds 10-20-20, 6 pounds 9-14-24 & 8oz SiMag 58 1 pound 10-20-20, 2.5 pounds 9-14-24, & 1.25oz (35gms) SiMag58 Apply 2-4 pounds of 4-18-38 as foliar.
8 14 pounds 9-14-24, & 8oz SiMag 58 2 pounds 9-14-24, & 1.25oz (35gms) SiMag58 Apply 2-4 pounds of 4-18-38 as foliar.
9 14 pounds 9-14-24 2 pounds 9-14-24 Discontinue fertigation as the vines will likely be at the end of their productive life.


Apply MetaCal or CalStore through the fertigation system weekly when not applying any P containing nutrients.  Fill irrigation lines with water, inject CalStore or MetaCal, then flush lines with clear water.  This will ensure that no clogging precipitates are formed, and that your developing fruit get plenty of Ca in balance with Mg.